Originally the movie Teenagers Battle the Thing (1958), this 1975 version is colorized and features additional footage. Generally about a group of students who go on an archaeological dig and uncover a monster.
This was actually made about 1964 by students at Chaffey High School in Ontario, California and shot in the orange groves of Cucamonga. The "professor" is the speech teacher at Chaffey, Bill Simonsen.
The beginning has been cut off here. That included a classroom scene that was cringe worthy. While slow paced and spoken, it is kind of fun and I like it better than the expanded version also on archive.org. This was purchased from the students and released to what must have been desperate movie houses in the 60s.